This can pretty much be applied to all parts of the bodies. I learned from observation, and it's a lot easier than people telling you how to draw in their style. PLEASE KEEP IN MIND THAT IN ORDER TO HAVE A MORE ACCURATE ANATOMY, YOU SHOULD USE REAL ANATOMY AND NOT SOMEONE ELSE'S. CHANCES ARE, THEIR ART IS VERY INACCURATE AND IT WILL ONLY MISLEAD YOU. ONLY USE IT FOR A BASIC IDEA.

I know you might want rawdi's advice but i think I can help a lil'.The Complete Book of Drawing and Anatomy for the artist.Both books are great at detail and description going into weight,muscle and bone structure.I also recommend looking at a shit ton of stock photo's.